design of a rectangular patch antenna

www.ijeee-apm.com International Journal of Electrical & Electronics Engineering 1

IJEEE, Vol. 1, Issue 1 (Jan-Feb 2014) e-ISSN: 1694-2310 | p-ISSN: 1694-2426

DESIGN OF A RECTANGULARPATCH ANTENNA

Amandeep Bath1, Abhishek Thakur2, Jitender Sharma3, Prof. Basudeo Prasad4

1,2,3,4Electronics & Communication Department, IGCE, Punjab, [email protected], [email protected],[email protected]

Abstract- This paper presents the idea of recentdevelopments and advancements in the field of wirelesstechnology to realize high speed communications whichis performed in wideband technology .In this paper thewideband patch antenna is designed and fabricated. Apatch antenna is a narrowband, wide beam antennawhich is fabricated by etching the antenna elementpattern in metal trace bonded to an insulating dielectricsubstrate, such as a printed circuit board, in which acontinuous metal layer bonded to the opposite side ofthe substrate and it produces a ground plane. Thesimulation is done using ANSOFT HFSS simulationsoftware.

Index Terms- Ultra Wide Band (UWB); WirelessLocal Area Network (WLAN); Industrial, Scientific,and Medical Band (ISMB).

I. INTRODUCTIONIn radio telecommunications, among the antenna

designs there are many different categories of microstrip antennas which are also known by the name printedantennas) the most common of which is the micro strippatch antenna or patch antenna. A patch antenna (alsoknown as a rectangular micro strip antenna) is a type ofradio antenna with a low profile, which can beconstructed on a flat surface. It consists of a flatrectangular metallic sheet or "patch" of metal, mountedover a larger metallic sheet called a ground plane. Theassembly is usually covered by a plastic radome, whichsaves the antenna structure from damage. Patchantennas are very simple to be fabricated and easy to bemodified and customized. They are the original type ofmicro strip antennas which were given by Howell in theyear 1972 in which the two metal sheets togetherproduce resonance and form a resonant piece of microstrip transmission line with a length which is around onehalf wavelength of the radio waves. The radiationprocess arises from discontinuities or irregularities ateach truncated edge of the micro strip transmission line.The radiation produced at the edges causes the antennato act slightly bigger electrically than its actual physicaldimensions, so in order for the antenna to be aresonanting piece of element, a length of micro striptransmission line slightly lesser than one half awavelength at the frequency is taken. A dielectricsubstrate is used for the construction of patch antenna,using the same. The easiest and most simple patchantenna uses a patch which is one half wavelength long,created at a precise distance above a larger groundplane, using an intermediary such as a spacer made of a

dielectric material between them. Electrically largeground planes produce very rugged and stable patternsand lower environmental sensitivity but of courseincrease the size of the antenna. It isn’t uncommon forthe ground plane to be only slightly larger than theactive patch. When a ground plane is near to the size ofthe radiator it can have the phenomenon of coupling andproduce currents along the edges of the ground planewhich also radiate. The antenna pattern is created as thecombination of the two sets of radiating metallicelements. The current which flows is along the directionof the feed wire, so the magnetic vector potential andalso the electric field follow the current. A simple andeasiest patch antenna of this category radiates a linearlypolarized wave. The radiation can be considered asbeing produced by a number of the “radiating slots’’ attop and bottom, or simultaneously as a result of thecurrent flowing on the patch and the ground plane.Commonly made micro strip antenna shapes are square,rectangular, circular and elliptical, but any continuousshape is possible and can be created. Some patchantennas do not use a dielectric substrate and instead aremade by using a metal patch mounted above a groundplane using dielectric spacers; the resulting structure isless rugged but the bandwidth is much wider. Now assuch antennas have a very low profile, are mechanicallyrugged and can be shaped and designed to conform tothe curving skin of a vehicle, they are often mounted onthe exterior of aircraft and spacecraft, or areincorporated and operated into electronic devices suchmobile radio communication equipments.[1-6]

Antenna's features such as frequency, radiationpattern and polarization are reconfigured to achieve thedemands for agile radio applications. A lot of researchesfocus on frequency reconfiguration as futurecommunication systems such as cognitive radio needsan antenna that can do spectrum sensing andcommunication. In designing of reconfigurablefrequency antennas, recently a reconfigurable wide-bandto agile narrowband frequencies, using a printed logperiodic dipole array antenna, was developed. Awideband slotted antenna has been produced usingmultifunctional reconfigurable frequency characteristicsfor various applications such Wireless LAN, WIMAX,Ultra wideband and UMTS has been proposed in afrequency reconfigurable antenna, made up of twostructural elements ; one is an ultra-wide band (UWB)and other is a frequency reconfigurable triangularshaped antenna, is proposed for cognitive radioapplications

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1) Ultra-wide band antennas have already been used inapplications such as satellite communication, remotesensing, ultra wide band radar technology and so on.Currently, the wireless area network (WLAN) in the 2.4-GHz (2.4-2.485 GHz) and 5-GHz (5.l5-5.875 GHz) bands isthe most renowned networks for accessing the internet andalso the antenna for an AP not only requires dual bandoperation but also needs to have an appropriate radiationprofile in both bands, namely equal gain, wide beam width,and high front-to-back ratio. Wireless communications isenjoying exponential growth in Industrial, Scientific, andMedical (ISM) band. The future generation wirelessnetworks require systems with broad band capabilities invarious environments to satisfy numerous applications assmart grid, personal communications, home, car, and officenetworking .On the other hand, many modern wirelesscommunication systems such as radar, navigation, satellite,and mobile applications use the circular polarized (CP)technology and radiation pattern. For the best UWBperformance, the transmitter and receiver (T/R) antennasshould have flat and high directive gain, narrow beam lowside and back lobes over the operational frequency band; toachieve the largest dynamic range, best focused illuminationarea, lowest T/R coupling, reduced ringing and uniformlyshaped impulse radiation.UWB has generally offers highdata rates at short distances with low power, primarily due tohigh resolution bandwidth.[7-11]

II. ANTENNA DESIGN AND CONFIGURATIONThe geometry and configuration of the proposed antenna

is shown in the figure. Initially the design properties areselected by adjusting the local variables such as the substratethickness, height, material, transparency and position aswell. As shown in the figure the proposed antenna consistsof a substrate on which a cylindrical coax of Teflon isdeveloped. The cylindrical coax pin is made up of thematerial pec. Also the height and radius of the coax are –16.67mm and 0.283mm respectively. The feed pin is alsocylindrical with a radius of 0.083mm and the height of62mil. Before covering the design with a radiation air boxthe circular wave port on the substrate with a radius of0.283mm is made. Finally the design is covered with avacuum air box before the simulation and analysis.

Fig. 1: Rectangular patch antenna

Fig. 2: Air box over the antennaThe impedance bandwidth of a patch antenna is stronglyinfluenced by the spacing between the patch and theground plane. As the patch is moved closer to theground plane, less energy is radiated and more energy isstored in the patch capacitance and inductance: that is,the quality factor Q of the antenna increases.A patch printed onto a dielectric board is often moreconvenient to fabricate and is a bit smaller, but thevolume of the antenna is decreased, so the bandwidthdecreases because the Q increases, roughly in proportionto the dielectric constant of the substrate. Patch antennasutilized by industry often use ground planes which areonly modestly larger than the patch, which also alterstheir performance.[12-13]A. Rectangular patch

The most commonly designed micro strip antennais a rectangular patch. The rectangular patch antenna isaround a one half wavelength long strip of rectangularmicro strip transmission line. When air is taken as theantenna substrate, the length of the rectangular microstrip antenna is approximately one half of a free spacewavelength. Antenna is loaded with a dielectricsubstrate. The length of the antenna reduces as therelative dielectric constant of the substrate elementincreases. The resonant length of the antenna is slightlylesser because of the increased electric "fringing fields"which increase the electrical length of the antennaslightly. An old model of the micro strip antenna is asection of micro strip transmission line with equivalentloads on either end to represent the radiation loss.B. Planar inverted F antenna

Another category of patch antenna is the PlanarInverted-F Antenna (PIFA) common in cellular phoneswith built-in antennas. (The Planar Inverted-F antenna(PIFA) is highly used in the mobile phone market. Theantenna is resonant at a quarter-wavelength (thusdecreasing the required space needed on the phone), andalso typically has good SAR properties. This antennaresembles an inverted F, which explains the PIFA name.The Planar Inverted-F Antenna is renowned because ithas a low profile and an Omni directional pattern. Theseantennas are produced from a quarter wave half patchantenna. The shorting plane of the half-patch isdecreased in length which decreases the frequency ofresonance. Often PIFA antennas have multiple branchesfor resonating at the multiple cellular bands. On somephones, grounded parasitic elements are applied toimproves the radiation bandwidth characteristics. [14-16]C. Advantages


Micro strip antennas are comparatively inexpensiveto manufacture and fabricate because of the easy 2dimensional physical construction and geometry. Theyare usually employed at UHF and other higherfrequencies because the size of the antenna is directlyrelated to the wavelength at the frequency of resonance.A single patch antenna gives a maximum directive gainof around 6bB to 9dB. It is relatively easy to print anarray of patches on a single (large) substrate andlithographic techniques are used for this. Patch arrayscan give much higher gains than a single patch at littleadditional expense; matching and adjustment of phasecan be performed with printed micro strip feedstructures, again in the same operations that producesthe radiating patches. The capability to create high gainarrays in a low-profile antenna is one reason that patcharrays are commonly used on airplanes and in othermilitary applications. Such an array of patch antennas isan easy way to design a phased array of antennas withdynamic beam forming capability. An advantageinherent to patch antennas is the skill to havepolarization diversity. Patch antennas can easily befabricated to have vertical, horizontal, right handcircular (RHCP) or left hand circular (LHCP)polarizations or different kinds of polarizations, usingmultiple feed points, or a single feed point withasymmetric patch structures. This unique feature enablespatch antennas to be used in many types ofcommunications links that may have variedrequirements.

III. PATCH ANTENNA DESIGN CONSIDERATIONWideband antenna are designed and fabricated for

smart grid applications with a frequency bandwidth of40% and gain of 3db to 4db . The antenna design andsimulation was carried out using ANSYS’ HFSS that isthe high frequency structure simulator software which isthe industry standard simulation tool for the simulationof 3D full wave electromagnetic field. The mostcommonly employed micro strip antenna is arectangular patch. The rectangular patch antenna isaround a one half wavelength long strip of rectangularmicro strip transmission line. When air is kept as theantenna substrate, the length of the rectangular microstrip antenna is approximately one half of a free spacewavelength. The length of the antenna reduces as theantenna is loaded with a dielectric as its substrate aswell as the relative dielectric constant of the substratehighly increases. The resonant length of the antenna isslightly lesser because of the incerased electric "fringingfields" which improve the electrical length of theantenna a little. An old model of the micro strip antennais a strip of micro strip transmission line with equalloads on either end to represent the radiation losses.

Fig. 3: Patch antenna design

It is possible to fabricate patch antennas that radiatewaves which are circularly polarized. One approach is toexcite a single square patch using two feeds, with onefeed with a phase difference of 90° with respect to theother. This drives each transverse mode and with equalamplitudes and the required 90 degrees out of phase.Each mode radiates separately and combines to producecircular polarization. This feed condition is oftenavailable using a 90 degree hybrid coupler. When theantenna is fed in this manner, the vertical current flow ismaximized and is high as the horizontal current flowbecomes zero, so the radiated electric field will bevertical; one quarter cycle later, the situation will havereversed and becomes opposite and the field will behorizontal. The radiated field rotates in time, producinga circularly polarized wave. An alternative is to use asingle feed but introducing some sort of asymmetric slotor other feature on the patch, causing the currentdistribution to be completely displaced. A square patchwhich has been perturbed slowly to produce arectangular micro strip antenna can be driven along adiagonal and create circular polarization. The aspectratio of this rectangle is chosen so each orthogonal modeis both non resonant. At the driving point of the antennaone mode is +45 degrees and the other -45 degrees andit is required to produce the 90 degree phase shift forcircular polarization.[16-20].

IV. RESULTS AND DISCUSSIONNow In this section the rectangular patch antenna is

designed and the numerical and experimental resultsregarding the radiation characteristics are presented anddiscussed. The simulated results are obtained by usingthe Ansoft simulation software high frequency structuresimulator. The measured and simulated characteristicsof the antenna are shown from the far field report of therectangular plot, the 3D polar plot and radiationcharacteristics.

Fig. 4: Return loss of antenna


A diagrammatic radiation pattern for a linearly-polarized 900MHz patch antenna is presented below.The figure shows a cross-section of a horizontal plane;the pattern in the vertical plane resembles though it isnot exactly identical. The scale is logarithmic, so thepower radiated at 180° (90° to the left of the beamcenter) is about 15 dB less than the power in the centerof the beam. The beam width is around 65° and the gainis approximately 9dB. An infinitely-big ground planeprevents any radiation which comes to the back of theantenna (angles from 180 to 360°), but the actualantenna has a fairly short ground plane, and the powerwhich comes in the backwards direction is only around20 dB down from that in comparison to the main beam.

Fig. 5: Radiation pattern of antenna

Fig. 6: Input impedanceof antenna

Unlike other antennas mentioned in literature todate, the proposed antenna presents a good Omnidirectional radiation pattern even at the very highfrequencies. The designed antenna has a very small sizeand even the return loss is low and radiation patterncharacteristics are obtained in the frequency band whichis used. The simulated and experimental results givesthe idea how that the proposed antenna could be a goodcandidate for UWB applications.

Fig. 7:ff_2D_Gain totalof antenna

Fig. 8: Return lossof antenna

As the length of the patch, half a wavelength, isabout the similar as the length of a resonating dipole, weget about 2 dB of gain out of the directivity relative tothe vertical axis of the patch antenna. If the patch iscompletely square, the pattern in the horizontal planewill be directional, somewhat as if the patch were a pairof dipoles which were separated by a half-wave; thiscounts for about another2-3 dB. Finally, the addition ofthe ground plane removes most or all radiation behindthe antenna, decreasing the power averaged over alldirections by a factor of around 2 (and therebyincreasing the gain by a factor of 3 dB). Summing thisall up, we get about 7-9 dB for a square element patch,in good agreement with more recognized approaches

Fig. 9: 3D polar plotof antenna

V. CONCLUSSION AND FUTURE WORKWith the rapid development of wireless

technology in recent years, various wireless systemssuch as GSM, WCDMA/UMTS, Bluetooth, WLANs,and GPS have been highly integrated into the mobileequipments, and in order to fulfill the RF systemrequirements using the different frequency band,antenna technology is required to wideband


characteristics .On the other hand, many modernwireless communication systems such as radar,navigation, satellite, and mobile applications use thecircular polarized (CP) radiation pattern. The attractivefeatures of the CP antenna are existed as follows.Firstly, since the CP antennas transmit and receive in allplanes all around, it is strong for the reflection andabsorption of the radio signal. In the multi-path fadingchannel environment, the CP antenna overcomes out ofphase problem which can create dead-spots, decreasedthroughput, reduced overall system performance.Further advancements could be done by using antennasubstrates with higher dielectric constants in order tominimize the size a broad band wide beam circularpolarization micro strip antenna. The configuration ofthe antenna is the simplest and easiest to be fabricatedas compared with conventional micro strip antenna, theradiation beam is broadened a lot. Further research oncircularly polarized wideband micro strip antenna isrequired as it gives the best performance and overallimprovement of antenna parameters.

REFERENCES[1] Gaboardi P., Rosa L., Cucinotta A., and Selleri S., “Patch

Array Antenna for UWB Radar Applications”, in3rdEuropean Radar Conference, 2006, p.281-284.

[2] Letestu and Ala Sharaiha, “Size reduced multi-bandprinted quadrifilar helical antenna,” IEEE Trans.Antennas Propag., vol. 59, pp. 3138-3143, 2011.

[3] A. Siligaris et al., “A 65-nm CMOS fully integratedtransceiver module for 60-GHz Wireless HDapplications,” IEEE Journal of Solid-State Circuits, vol.46, no. 12, pp. 3005-3017, Dec. 2011.

[4] S. Manafi, S. Nikmehr, and M. Bemani, "Planarreconfigurable multifunctional antenna for WLAN/wimax/ UWB/ pcsdcs/ UMTS applications," Progress InElectromagnetic Research C, Vol. 26, 123- 137, 2012.

[5] F. Ghanem, P. S. Hall and J. R. Kelly, “Two portfrequency reconfigurable antenna for cognitive radios”,Electronics Letters,vol.45, 2009,pp.534-536.

[6] C. R. Medeiros, E. B. Lima, 1. R. Costa, and C. A.Fernandes, "Wideband slot antenna for WLAN accesspoint," IEEE Antenna Wireless Propagate. Lett., vol.9,pp. 79-82, 2010.

[7] E. Ebrahimi, J. R. Kelly and P. S. Hall, “Areconfigurable Narrowband antenna integrated withwideband monopole for cognitive radio applications”,IEEE Antennas and Propagation Society InternationalSymposium (APSURSI), 2009.

[8] J. W. Baik, S. Pyo, T.H. Lee, and Y.S. Kim, “Switchableprinted Yagi Uda antenna with pattern reconfiguration”,ETRI Journal, vol.31 2009,pp.318-320.

[9] M. Sanad, "A Small Size Micro strip Antenna Circuit",IEEE International Conference on Antenna andPropagation, vol. 1, pp. 465-471, April1995.

[10] P. Suraj and V. R. Gupta, “Analysis of a RectangularMonopole Patch Antenna” International Journal ofRecent Trends in Engineering, Vol. 2, No. 5, pp. 106-109, November 2009.

[11] M. N. Srifi, M. Meloui and M. Essaaidi, “RectangularSlotted Patch Antenna for 5-6GHz Applications”,International Journal of Microwave and OpticalTechnology, Vol.5 No. 2, pp., 52-57 March 2010.

[12] Ansoft Corporations, HFSS V.12- Software based on thefinite element method.

[13] G. Augustin, S. V. Shynu, C. K. Aanandan, and K.Vasudevan, "Compact dual band antenna for wireless

access point, " Electron. Lett., vol. 42, no. 9, pp. 502-503, Apr. 2006.

[14] S. W. Su, "Concurrent dual-band six-loop-antennasystem with wide 3-dB beam width radiation for MTMOaccess point, " Microwave Opt. Techn. Lett., vol. 52, no.6, pp. 1253-1258, Jun. 2010.

[15] S. W. Su, "High-gain dual-loop antenna for MTMOaccess point in the 2.4/5.2/5.8 GHz bands, " IEEE Trans.Antenna Propag., vol. 58, no. 7, pp. 2412-2419, Jul.2010.

[16] K.B. Hsieh, M.H. Chen, and K.L. Wong, "Single feedDual Band Circularly Polarized Micro strip antenna,"Electron. Lett. VOL. 34, pp.1170-1171,Jun.1998

[17] G. P. Jin, D.L. Zhang and R.L. Li, “Optically controlledReconfigurable antenna for cognitive radiosapplications”, Electronics Letters, vol.47, pp.948-950,2011.

[18] Wang Yazhou, Su Donglin, Xiao Yongxuan,“Broadband circularly polarized square micro stripantenna”, Antennas, Propagation and EM Theory, 2006,ISAPE 2006 7th International Symposium on, pp.1–4,2006.

[19] LTCC hybrid coupler, “RCP1850S03N”, RN2Technologies co.Zhen-Yu Zhang, Yong-Xin Guo, Ling Chuen Ong, ChiaM.Y.W., “A New wide-band planar balun on a singlelayer PCB”, Microwave and Wireless ComponentsLetters, IEEE, Vol. 15, No. 6, pp. 416–18, Jun. 2005.

AUTHORSFirst Author – Amandeep BatthM. Tech. in Electronics andCommunication Engineeringfrom Punjab TechnicalUniversity, MBA in HumanResource Management fromPunjab Technical University ,Bachelor in Technology (B-

Tech.)from Punjab Technical University . Six years ofwork experience in teaching. Area of interest: AntennaDesign and Wireless Communication. InternationalPublication: 1, National Conferences and Publication: 4.Working with Indo Global College of EngineeringAbhipur, Mohali, P.B. since 2008.Email address: [email protected]

Second Author– AbhishekThakur: M. Tech. in Electronicsand Communication Engineeringfrom Punjab TechnicalUniversity, MBA in InformationTechnology from SymbiosisPune, M.H. Bachelor inElectronics (B.E.) from ShivajiUniversity Kolhapur, M.H. Five

years of work experience in teaching and one year ofwork experience in industry. Area of interest: DigitalImage and Speech Processing, Antenna Design andWireless Communication. International Publication: 7,National Conferences and Publication: 6, BookPublished: 5 (Microprocessor and Assembly LanguageProgramming, Microprocessor and Microcontroller,Digital Communication and Wireless Communication).Working with Indo Global College of EngineeringAbhipur, Mohali, P.B. since 2011.Email address: [email protected]


Third Author – Jitender Sharma: M. Tech. inElectronics and Communication Engineering fromMullana University, Ambala, Bachelor in Technology(B-Tech.)from Punjab Technical University . Five yearsof work experience in teaching. Area of interest:,Antenna Design and Wireless Communication.International Publication: 1 National Conferences and

Publication:6 and Wireless Communication). Workingwith Indo Global college since 2008E-mail address:[email protected]